Initiation aimed explosive devices

ABSTRACT

The detonation of charge-around-case explosive devices is accomplished by combinations of initiation logic, detonation wave interactions, controlled case forming implosion and analog-todigital methods of path control to enhance the directionality, projection of kill mechanism and environmental coupling of the charge in a variety of warhead/target intercept conditions. Numerous variants are developed to give a wide choice of geometries and complexity.

Silvia June 28, 1974 I INITIATION AIMED EXPLOSIVE DEVICES [76] Inventor:Denis A. Silvia, 7 Shalimar Dr.,

Shalimar, Fla. 32579 [22] Filed: Feb. 20, 1970 [21] Appl. No.: 13,237

[52] US. Cl. 102/22, 102/100 [51] Int. Cl F421! 3/00 [58] Field ofSearch 102/22, 24 R, DIG. 2, 67,

[56] References Cited UNITED STATES PATENTS 2,999,458 9/1961 Coursen....102/22 3,016,831 l/1962 Coursen.... 102/22 3,035,518 5/1962 Coursen 4102/22 3,170,402 2/1965 Morton et al..... 102/DIG. 2 3,280,743 10/1966Ruether l02/DIG. 2 3,311,055 3/1967 Stresau, Jr. et a1. 102/22 3,430,5643/1969 Silvia et al. 102/22 3,435,763 4/1969 Lavine l02/DIG. 2

3,447,463 6/1969 Lavine 102/67 3,490,372 l/l970 Lavine 3,598,051 8/1971Avery 102/23 FOREIGN PATENTS OR APPLICATIONS 1,138,654 1/1969 GreatBritain 102/D1G. 2

Primary Examiner-Robert F. Stahl Attorney, Agent, or Firm-Sughrue,Rothwell, Mion, Zinn and Macpeak ABSTRACT The detonation ofcharge-around-case explosive devices is accomplished by combinations ofinitiation logic, detonation wave interactions, controlled case formingimplosion and analog-to-digital methods of path control to enhance thedirectionality, projection of kill mechanism and environmental couplingof the charge in a variety of warhead/target intercept conditions.Numerous variants are developed to give a wide choice of geometries andcomplexity.

19 Claims, 52 Drawing Figures 'PATENTEDJUN281H74 3 820 461 SHEEY 1 [IF 9I I ATTORNEYS PATENTl-imunza m4 SHEET 3 UF 9 FATENTED JUN 2 8 IBM SHEEYS [If 9 PATENTEDJUH 28 1974 SHEET 7 BF 9 zzzzzzzzf INITIATION AIMEDEXPLOSIVE DEVICES BACKGROUND OF THE INVENTION 1. Field of the InventionThe present invention is directed to explosive charges and morespecifically to arrangements of explosive, case and buffer materials forinitiating and controlling the detonation thereof to improve thedirectionality and/or coupling to case and environment. New initiationand buffering techniques have been developed to accomplish this.

2. Prior Art In the past warheads were usually formed of a metal casefilled with a homogeneous mass of explosive which was isotropicallydetonated so that the fragments of the metal case would be propagatedalong a path substantially normal to the local surface of the warhead.At the most, the fragments could be deflected about 7 from normal andsince the fragments were moving outwardly in all directions it wasimpossible to obtain any concentration of the fragments to provide amore effective fragmentation pattern in any specific direction. Mostconventional warheads do not impact the target directly but encounterthe target along one side or the other. When a warhead explodes thetarget subtends only a small angle about the warhead center. Makingallowance for fuse inaccuracies, the target distribution will generallyextend about 17/4 radians about a side- Iooking cylindrical warhead.Thus, more than half the case fragments are directed away from thetarget, even with maximum aiming in a case-around-charge design.

With the inability of assymetric initiation techniques to substantiallyimprove kill-mechanism efficiency, several variable geometry approacheshave been tried. These methods attempt to re-orient the warheadcomponentsjust prior to detonation. Unfortunately, certain difficultiesmilitate against this method. Rapid deployment in a high speed airstream creates impossible aerodynamic problems and even the fastestmechanical movement has proven too slow in high speed interceptconditions.

Current fuse technology uses a variety of sensors to detect and trackthe target distribution centroid. The fuse initiates the warhead atachievement of the optimum geometric relationship vis-a-vis the target.Sidelooking air-air fuses which locate not only the polar but theazimuthal target coordinate sector as well have been successfullytested. These fuses give the warhead two pieces of information, namelywhen to detonate and what direction to aim. Because of the primitivestate of explosive control prior to the present invention,

these fuses have been designed to communicate with parallel logic to thewarhead. For example an eight-way aiming warhead would require eightdetonators, each with a safe-arming mechanism. The fuse would choose theappropriate detonator to fire.

SUMMARY OF THE INVENTION i the appropriate aim direction. Any number ofaim directions may be selected by serial coding (time sequencing) onlytwo detonators.

The present invention also comprises numerous single point, sequenced,muIti-point and line initiation methods which are adaptable to realisticwarhead packages and which operate in conjunction with the secondaryexplosive network means.

The present invention further comprises analog-to digital conversions ofthe detonation of the warhead explosive mass to provide control of theeffective detonation velocity.

The present invention also comprises a unique means of using thesacrificial explosive itself as an incendiary/- reactive kill-mechanism.Generalization of this concept allows variable C/M (charge mass/metalmass) constructions.

Various combinations of the above features may be made to provide animproved warhead construction.

The present invention provides an improved arrange ment of theexplosive, case and buffer materials for use with the above networkmeans, initiation methods and detonation velocity control to provide amore effective warhead with a more efficient concentration offragmentation and a more effective utilization of the explosive force.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showingthe fragmentation of a conventional prior art warhead.

FIG. 2 (ad) shows the explosive sequence for a cylindrical warheadhaving the charge surrounding a casing with insufficient velocity ofcollapse to achieve ejection from the surround.

FIG. 3 (a-d) shows the explosive sequence according to the presentinvention for a cylindrical warhead hav ing the charge surrounding theliner, the liner being thin enough to achieve ejection.

FIG. 4 (a-c) schematically shows several conceptual modifiedarrangements for the explosive material to effectively extend the pathof the explosive detonation around the periphery on the cylindricalcharge.

FIG. 5 shows another embodiment of the present invention wherein a ringcharge is utilized to detonate at least one explosive charge locatedradially outwardly thereof.

FIG. 6 is a schematic view showing the problem encountered with the twopoint detonation of a ring or cylindrical charge.

FIG. 7 is a schematic view similar to FIG. 6 but utilizing a pluralityof explosive diodes to render a two point detonation feasible.

FIG. 8 is a schematic sectional view of a warhead according to thepresent invention showing the relationship between the detonation ringand the main explosive charge.

FIG. 9 is a fragmented detailed view of the end'plates shown in FIG. 8.

FIG. 10 (a-c) is a schematic view of a diode network for connecting theexplosive elements of the warhead shown in FIG. 8.

FIG. 11 shows an electrical diode network corresponding to the explosivediode network of FIG. 10.

FIG. 12 is a schematic view showing the details of a linear diode.

FIG. 13 is a schematic cross-sectional view of an explosive diodenetwork to accomplish line detonation of the explosive means shown inFIG. 10 utilizing linear diodes.

FIG. 14 is a partial view of an explosive logic element according to thepresent invention for controlling the commencement of detonation of aselected explosive segment in an explosive means.

FIGS. 15a and 15b are explanatory schematic views showing the operationof the explosive logic element in FIG. 14.

FIG. 16 is a schematic sectional view of a modification of the presentinvention providing for isotropic initiation in the event of fusefailure.

FIG. 17a is a schematic view of an initiation ring similar to FIG. 16for an eight sector warhead.

FIGS. 17b and 17c are schematic views of modified isotropic initiationdevices.

FIG. 18 is a schematic cross sectional view of a simple detonation delayfor end initiated explosive segments arranged around a cylindrical case.

FIG. 19 is an elevation view, partly in section, of FIG. 18.

FIG. 20 is a schematic sectional view of a planar detonation controlsystem for arbitrary surfaces.

FIG. 21 is a schematic flow diagram for the shock waves showing theirpath of travel in FIG. 20.

FIG. 22 is a schematic top plan view of the arrangement shown in FIGS.20 and 21.

FIG. 23 is a sectional view of an hexagonal array of explosive elementsutilizing the diode interconnection of FIG. 20.

FIG. 24 is a schematic view showing the diode interconnections of theexplosive segments of FIG. 23.

FIG. 25 is a sectional schematic view similar to FIG. 20 showing therelationship of continuation segments to the dilation elements.

FIG. 26 is a cross sectional schematic view of a warhead utilizing thearrangement of FIG. 25 to provide explosive shaping of the case.

FIG. 27 is a schematic plan view of a warhead having a cylindricalcharge filled with a fragmentation core.

FIG. 28 is a schematic view of an arrangement similar to FIG. 27 showinga detonation sequence to achieve directionality of the fragmentationcore.

FIG. 29 is a cross sectional view taken generally along the line 29-29in FIG. 28.

FIG. 30 is a schematic view showing the arrangement of pyrocore in eachexplosive segment.

FIG. 31 is a schematic sectional view showing a modified asymmetrictiming arrangement similar to FIG. 19.

F lg. 32 is a schematic sectional view of an arrangement for sequencingexplosive segments by means of metal shock prisms.

FIG. 33 shows a plurality of circular T-shaped linear AND gates shockedconcentrically about an explosive core.

FIG. 34 is a schematic view of a typical line wave generator.

FIG. 35 shows a buffer device for eliminating collision fronts in theline wave generator of FIG. 34.

FIG. 36 is a cross sectional schematic view of a line detonating sheathshowing a plurality of linear AND gates.

FIG. 37 is a schematic view of clustered AND gates, either linear orplanar.

FIG. 38 is a modified schematic view of two sets of clustered, opposedlinear or planar AND gates with a shaped-charge" bootleg.

FIG. 39 is a modification of the opposed linear or planar AND gates withcontrolled delays to permit the outer set to pass through the inner set.

DETAILED DESCRIPTION OF THE INVENTION Although the isotropic detonationof many warheads is acceptable and sometimes even desirable there arenumerous times when it is desirable to concentrate the explosive killmechanism in a specific lateral direction relative to the direction oftravel of the warhead. Oftentimes a missile having a cylindrical warheadmerely approaches the general vicinity of the target and is so set upthat it will explode as the missile passes the target. In situationssuch as this, the entire kill shouldbe directed transversely to the axisof the cylindrical warhead in a direction toward the target. Such anobjective is impossible if the cylindrical warhead is isotropicallydetonated thereby sending the fragments of the surrounding casingradially outwardly 360 about the axis of the cylindrical warhead. Suchan arrangement is shown in FIG. 1 wherein a cylindrical warhead 10 isdetonated in close proximity to a target 12. The arrows 14 show thepattern of the fragments and it is obvious that only those fragments ofthe warhead casing subtended by the angle a will effectively reach thetarget 12. Thus, the majority of the case fragments are directed awayfrom the target in a case-around-charge design even with the bestselection of initiation points.

With the inability of initiation techniques to improve thekill-mechanism efficiency, several variable geometry approaches havebeen tried in the past. These methods attempted to reorient the warheadcomponents just prior to detonation. However, rapid deployment in a highspeed air stream creates impossible aerodynamic problems while even thefastest mechanical movement has proven to be too slow for high speedintercept conditions.

In an effort to overcome these deficiencies, the arrangement shown inFIG. 2 was attempted wherein the cylindrical charge 16 surrounds ahollow casing or killmechanism 18. If the cylindrical charge isdetonated along the line 20 in FIG. 2a which is on the opposite side ofthe casing 18 from the target, the liner or casing 18 is initiallydriven toward the target as shown by the sequence in FIGS. 2a-2c.However, simultaneously, the

- detonation is proceeding around the casing by a detonation rate ofabout 25,000 feet per second. This is generally many times faster thanthe fragment velocity so the detonation quickly surrounds the casing orcore nullifying the initial impulse as was clearly shown in FIG. 2d. Theonly way the full benefits of this design can be obtained is for theinner shell or casing 18 to cross the warhead diameter before the armsof the detonation can meet as they travel in opposite directions aroundthe cylindrical charge. If this can be accomplished the fragmentvelocity will be given an extra boost rather than being impeded.

In order to accomplish this the detonation is line initiated parallel tothe cylinder axis as shown in FIG. 3a. By detonating the bifurcatedcharge 20 at a point spaced from and parallel to the hollow cylindricalcharge two separate explosive waves will collide in the cylindricalcharge thereby giving the linear an initially sharp peak. This is verydesirable for both ease of crossing the void and the formation of aknife-like slug. The high C/ M (charge mass/ metal mass) would beprimarily for high speed encounters or armor penetration. The

detonation and liner collapse will proceed as shown in the sequence ofFIGS. 3a3d. As most clearly shown in FIG. 3d, the final explosivedetonations of the cylindrical charge will meet after the liner hasstarted to move outwardly through the charge so that the final explosivedetonations will aid rather than oppose the liner ejection from thecharge.

The velocity v of the liner can be approximated according to thefollowing formula:

v k(D+d)/21r(l l-d) inches per in./,u.-sec. where k is the scale factor(how many diameters the liner travels), d is the inner'shell diameter, Dis the outer shell diameter and 11' (D+d) u-sec. equals the time it willtake detonation to travel halfway around the cylindrical charge to apoint opposite the point of initiation. Thus, d= k/2 1r exp 6/12)feet/seconds.

v =k(4/3) X 10 exp 4 feet/sec.= 11,333 feet per second where k equals 1.

The required liner velocity of nearly 12,000 feet per second is quitehigh but should be achievable.

In a cylindrical warhead several techniques are available to help, suchas having a high C/M and evacuating the core. By evacuating the core theenergy transferred to the case is improved and pressure-volume workingof air in the central void is eliminated. Line detonation also helpsoptimize the detonation head and sequenced initiation along thez-coordinate long axis of the cylinder will provide confinement on thez-axis by creating surfaces of shock collision, thereby utilizing thecollision surfaces as artificial confinement.

As an alternative to imparting an extremely high speed to the liner asit is projected across the central void in order-to obtaindirectionality it is possible to obtain an equally effective design ifthe detonation simply takes longer to travel its path around thecircumference of the cylindrical charge. It is not practical to lowerthe detonation velocity directly but the effective velocity can belowered by increasing the path length. Such an arrangement is shown in arather primitive form in FIG. 4a wherein a portion of the cylindricalcharge 24 is shown arranged in a sinusoidal manner so that if detonationtakes place at point 26 the explosion will have to travel a much longerpath to reach a point diametrically opposite from point 26. A morerefined version of the elongated path is shown in FIG. 4b wherein theexplosive ring 28 has a plurality of notches 30 extending inwardly fromthe circumference and alternated with a plurality of indentations 32extending outwardly into the ring. In FIG. 40 a variation of theconstruction shown in FIG. 4b is shown to obtain shock converging (ordiverging if desired) in all sectors instead of alternating as shown inFIG. 4b.

The above principles of operation can also be applied to theconstruction of a detonation ring which in turn would initiate theexplosion of another explosive charge in a warhead. An example of suchan arrangement is shown in FIG. 5 wherein a thin ring 40 of highexplosive material is detonated at point 42. The explosion travels inopposite directions around the ring 40 and meets at point 44 therebycausing a jet effect which will penetrate a buffer ring 46 and detonatethe high explosive charge 48 located radially outwardly thereof.

In order'to vary the point on the ring where the detonation collisionwill take place, it is possible to detonate the ring at two spaced apartselected locations according to a predetermined timing sequence. Asshown in FIG. 6 it is possible to obtain a detonation collision at anypoint along the short are of ring 50 between A and B by varying thetiming of the detonation at each of these points. Unfortunately, therewill also be an image point where a collision will occur. If the desireddetonation is at point 52 then it is obvious that the detonation atpoint A has proceeded through an angle a and the detonation from point Bhas proceeded through an angle B. Meanwhile, the detonations haveproceeded in the opposite directions from A and B through angles a andB, respectively and the collision image will occur at the midpoint ofthe remaining angle. Assuming a third detonation source or point C isadded to the ring 50 and the three detonation points A, B and C areequally spaced about the ring it will be possible to sequence A and B toobtain collision on their short arc at a predetermined location. Onceagain an image point is formed but to produce the image point one of theA, B detonation arms must pass through point C.

By arranging the three points A, B and C as shown in FIG. 7 at equallyspaced apart locations on the ring 54 v and inserting two blockingdiodes 56 and 58 on either side of point C the suppression of the imagepoint can be obtained. Since the detonation could occur at any two ofthree points, it is necessary to locate the diodes 60 and 62 on eitherside of point A and diodes 64 and 66 on either side of point B. Thediodes may be constructed and arranged in accordance with the disclosureset forth in US. Pat. No. 3,430,564, granted Mar. 4, 1969. Assumingdetonations occur at points A and B of FIG. 7 in the same sequence asdescribed above with respect to FIG. 6 the explosions will meet atapproximately point D. The explosions traveling along the segment 68from point B toward point C will pass unimpeded through diode 64 butwill be extinguished by diode 58 before it can meet with the explosiontraveling along segment 70 from point A toward point C. Thus, thedesired collision and subsequent jetting can be accomplished along anyof the three arcs of the ring at a predetermined location by properlydetonating any two out of the three detonation points in the proper sequence and the collision of the explosions will be prevented.

A practical arrangement for a detonation ring such as described in FIG.7 is shown in FIG. 8 wherein a cylindrical warhead is provided with athin outer case 72 and a cylindrical explosive charge and liner 74interiorly thereof. A pair of explosive end plates 76 and 78 areprovided and the detonation ring 80 or one of the other multiplexersdetailed later is located within the hollow cylindrical explosive charge74. Only two safe arming devices are necessary in the fuse 81 whilestill maintaining the ability to selectively detonate in any desiredarming direction. The explosive end plate 78 may be separated into pieshaped wedges as shown in FIG. 9 so that the end plate detonation issynchronized with the detonation of the warhead segments.

Reverting to the cylindrical arrangement of the high explosive materialsuch as shown in FIGS. 4a 4c in order to accomplish a longer effectivedetonation path, it is noted that it is also possible to provide aplurality of individual explosive segments connected together by anexplosive diode network to provide the proper sequencing and timing.Such an arrangement is shown in FIG. 10a wherein the ring generallydesignated at 80 is divided into a plurality of explosive segments 82and 84 separated and connected by means of a suitable diode network 86.FIG. 10b shows an enlarged detailed view of the diode network arrangedbetween the two segments 82 and 84 and FIG. 10c shows a detailedexploded view of the diode network. The diode network is constructedfrom three buffer plates 88, 90 and 92 with the high explosive diodeformed in cutout portions of the buffer plate 90. Each of the outermostplates 88, 92 of the sandwich arrangement are provided with cylindricalbores 94 filled with high explosive. These bores are aligned with theends of the diodes 89 and 91 formed in the intermediate buffer plate 90.In operation, if the charge segment 84 is initiated first at the lefthand end as viewed in FIG. 10b, the explosion will travel in thedirection of the arrow until it reaches the explosive charge 94intermediate the ends of the charge segment 84. The explosion will thentravel through the diode in the direction shown by the arrows andinitiate the explosion of the charge element 82 and so on around thecylindrical network. The electrical analog of the diode network is shownin FIG. 11.

The foregoing arrangement of the explosive segments connected by meansof a diode network are suitable for end initiated explosions such aspreviously discussed above with respect to FIG. 8. However, the delayedpath techniques may also be applied to a line initiated warhead and theproper operation for any aim point requires a network of the same typeas that used for the end initiated warhead. In this case, however, a newlogic device, the linear diode, is required to maintain line initiation.The linear diode is an extension of the explosive diodes disclosed inthe classified successor to US. Pat. No. 3,430,564. Such a linear diode100 is disclosed in FIG. 12 and is comprised of two planar sectionsdisposed at right angles to each other with one planar section 102having a thickness considerably less than the thickness of planarsection 104. This arrangement utilizes the corner effect which is aphenomenon which takes place when a thin explosive layer is detonatedalong its surface. The thickness required is dependent upon theexplosive used. For duPont EL 506-C sheet explosive this layer is about.025 inches. More sensitive compositions may require a thinner layer andless sensitive explosives require a thicker one. The thickness isgenerally called the critical thickness and is just sufficient tosustain a detonation. At these thickness levels the detonation can beinhibited easily especially by sharp changes of direction and the cornereffect occurs when shock is forced around a sharp corner. Under theseconditions, the shock must swing Wide around the corner leaving asizeable half moon 106 of undetonated explosive. By making the channelinto which the shock is trying to turn so narrow that its terminal endat the corner is entirely within the undetonated region the shock simplyruns out of explosive and shuts itself off. Thus, the explosive cannotturn from a wide channel into a narrow one even though a shock comingfrom the'narrow channel into-the wide one has no difficulty negotiatingthe corner. Thus, we have an explosive diode with a continuous path ofsecondary explosive.

By utilizing the linear diodes described above the various segments ofthe warhead may be each connected together by a quartet of linear diodesin the manner shown in FIG. 13. The explosive segments 110 and 112 areseparated by four buffer elements 114, 116, 118 and 120 arranged withrespect to each other so as to provide wide channels 122, 124, 126 and128 and narrow channels 130, 132, 134 and 136. Thus, an explosioninitiating in segment will proceed through channels 122 and 134. Sincethe explosion proceeding through narrow channel 134 enters into widechannel 126 the explosion will be able to turn the corner and proceedthrough the central chamber 138 whereas the explosion proceeding throughwide channel 122 is quenched since it cannot make the turn into narrowchannel 130. Likewise, as the explosion proceeds through central chamber138, the explosion entering passage 128 will be quenched since it cannotmake the turn into narrow channel 136 whereas the explosion passingthrough narrow channel 132 can make the turn into wide channel 124 andthus initiate the explosion of segment 112. Thus, the line initiation ofeach segment is accomplished in the proper sequence and with the propertiming so as to effectively lengthen the path of travel of the explosionaround the circumference of the warhead.

A linear AND gate is accomplished with the arrangement shown in FIGS. 14and 15 by utilizing the flag or comer effect. An explosion or detonationstarted and traveling along the top arm 140 is maintained due to thesufiicient thickness of the top arm but the vertical arm 142 is too thinand the detonation is trying to die but is continually renewed by theprogressing detonation of the top arm as shown by the wavefront 146. Aplurality of horizontal output channels 148 and 150 are connected to thevertical arm 142 and if the shock is only traveling along the top armand vertical segment the shock wave will be too weak to turn the cornerfrom the vertical segment 142 into the horizontal segment 148 and 150 asbest shown in FIG. 15b. However, if a detonation is progressing in theopposite direction on the bottom arm 152 a similar dying shock will betraveling along the narrower vertical arm 142. When the two dying shocksmeet each other as shown in FIG. 15b, the two dying shocks aresufficient to give an output into the horizontal arm 148 or 150depending upon the point where the detonation of the top arm 140 and thebottom arm 152 meet. Thus, by properly sequencing the detonations in thetop and bottom arms a selected output segment may be intiated which inturn will initiate the proper segment of a cylindrical warhead to givethe desired aimed detonation of the warhead.

Another form of demultiplexer ring for cylindrical warheads is shown inFIGS. 16 and 17. In FIG. 16 the fuses deliver pulses to the highexplosive channel in timed sequence at points I and II so that thedetonations proceed in opposite directions around the channel 160 andmeet at point 162. When the detonations meet at point 162 the explosionwill jet through the buffer 164 to initiate the cylindricalwarhead 166at this point. Simultaneously, detonations proceed along channels 168and 170 from points I and II into a delay 172 which is effectivelylonger than the channel 160. Thus, if either of the fuses should fail adetonation will travel through the delay 172 to initiate a centralisotropic detonation of the warhead.

FIG. 17a shows the isotropic initiation of FIG. 16 arranged within ahollow cylindrical warhead having eight high explosive segments 174separated by buffer strips 176. By choosing the proper time sequence ofthe fuses I and II the explosion is traveling in opposite directionsalong the channel 160 will meet adjacent a predetermined high explosivesector and jet through the buffer wall 164 to detonate the selected highexplosive segment 174.

FIG. 17b shows a variation in the configuration of the high explosivechannel 160 in FIGS. 16 and 17a. If one of the detonators should fail toinitiate the explosion within the channel 160 at point A or point B theexplosion from the other point will travel completely around the channel160 and enter the heart shaped isotropic output channel 178. A similarisotropic output can be achieved from the T-shaped initiation ring shownin FIG. 17c which is similar to the ring shown and described withrespect to FIGS. 14 and 15. Thus, if one of the detonators fail toinitiate an explosion in either channel 140 or channel 152 there willnot be explosions traveling in opposite directions to generate an outputin the high explosive segments 150 shown in dotted lines. Thus, thesingle explosion will travel completely around the T-shaped ring andenter an isotropic output channel similar to that shown in FIG. 17b.Null gates turn-off isotropic leads at B, A when detonation results atA, B respectively, thus preventing isotropic interference with normaloperation.

In FIG. 18 the high explosive segments 180 are arranged about a core(solid or hollow) 182 and are separated from each other by means ofindividual buffer strips 184. This is somewhat similar to thearrangement of high explosive segments shown in FIG. but instead ofconnecting the various segments by means of a diode arrangement,U-shaped lengths of MDF (mild detonating fuse) I86 extend between thesegments 180 through the buffer walls 184. The initiation logic,complete with detonators, safe-arming and electrical terminals could beassembled on a plastic disc and secured directly to the top end of thewarhead as viewed in FIG. 19. Thus, upon initiation of the explosion ofone of the segments 180, the explosion would travel along the MDF 186into the adjacent high explosive segments 180 on either side thereof todetonate the segments with the appropriate time delay. Thus, theexplosion would travel from segment to segment in opposite directions toobtain the proper aiming of the explosive force and fragmentationpattern. The core 182 may be closed with end plates and evacuated asdiscussed previously or may be filled with a fragmentation core asdiscussed more in detail hereinafter. A typical construction techniquemight be to mold a plastic form into a metal case wherein both insideand outside shells of the case could be made in one piece to insurerigidity. After assembling the MDF or similar sheathed detonating cord,the main charge would be loaded. The plastic would serve as aform forthe MDF, a mold for the main charge and a buffer. The metal shells wouldserve as both a kill-mechanism and the load bearing structure, The onlycritical part (the initiation logic) being contained on a sturdy plasticdisc, the design would allow significant cost reductions in addition tosion is propagated from explosive segment to'explosive segment only in apredetermined direction.

FIG. 22 shows an arrangement of high explosive segments 198 having theMDF cord 200 arranged centrally of each sector with diodeinterconnections designated by the lines 202 extending therefrom to eachof the four sectors located adjacent the four sides of the main sectorrespectively. Each of the branches 202 is formed with a diode similar tothat described above at 196 so that the explosive force may travel onlyfrom a major section 198 to an adjacent sector and upwardly through theMDF cord 200 to initiate the adjacent sector 198. Utilizing theprincipal body of this arrangement the individual explosive segments 198may take any suitable geometry such as the hexagonal array shown inFIGS. 23 and 24. The isochrone 204 in FIG. 23 is complete and concentricabout the original point of destination 2% and the arrangement of thediode connections between the various hexagonal segments to achieve thisisochrone is shown in FIG. 24. The isochrones have the same shape as theelement in cross section but are rotated so that the locations of sideand angle are interchanged. Although the elements can be of any size andshape, space-filling shapes of uniform size would be preferred inpractical applications. Since the time dilation depends upon bothelement size and length, both of which are infinitely variable withinlimits, any reasonable dilation can be achieved. In practice,requirements vary from about 4:1 for light case warheads to about 8:1for heavy cased charges. To minimize the parasitic loss due to bufferingthe element size (or grain) would be the largest consistent withrequired uniformity. Since regular hexagons are the most nearly circularof regular figures that fill the plane, the

markedly improving the performance over conventional warheads.

A variation of the detonation control shown in FIGS. 18 and 19 isachieved in FIG. 20 wherein the MDF or sheathed detonating cord 188extends between the explosive segment l90and is formed into a diode 192in the manner previously described. The diode 192 is formed with a wideleg I94 and a narrow leg 196 so that the explosion can only turn thecorner in one direction. The net result of this arrangement is theexplosion path pattern shown in FIG. 21 so that the exploelements wouldnormally take that shape although other shapes might be chosen to fitexternal geometries, e.g. make the isochrones confront the caseuniformly.

For a long charge, the element chosen for proper time dilation may notbe more than a small fraction of the overall charge length. As shown inFIG. 25 continuation segments 208 of high explosive may be provided toaccomplish this. Such continuation segments may be utilized to assist informing the fragmentation dart as shown in FIG. 6 wherein the casing 210is disposed adjacent the end of a plurality of continuation segments 212which in turn are aligned with the individual elements of an array 214of dilation elements similar to that shown in FIG. 23. In this way theshock waves designated by the lines 216 will reach the fragmentationplate at a predetemiined time sequence to achieve the fragmentation formshown in dotted lines at 218.

As mentioned before, the aimed warhead is first optimized in its grossgeometry. The inside-out or chargearound-case design is consideredoptimum if all-way aiming is desired. The two main variants are thehollow and solid designs with the hollow design being discussedpreviously with respect to FIG. 3. Such a design delivers a very narrow,dense fragment beam, similar to a focused or shaped charge. The solid orfragment core variation offers advantages if a more dispersed but stillaimed warhead is desired. The primitive fragment core has beenpreviously proposed but without control proved to be ineffective.

Considering the basic fragment-core design in FIG. 27, it is noted thatthe core 219 is formed from a plurality of segments which completelyfill the internal portion of the casing about which the high explosivecharge 220 is disposed. Assuming the charge is detonated at 222, the aimdirection will then be along the arrow 224 on the opposite side of thecharge. The core, although initially driven in the end direction upondetonation of the high explosive, subsequently experiences an almostequal impulse in the opposite direction because the detonation velocityis about five times that of the core. Therefore, the explosion travelscompletely around the high explosive ring before the fragmentation corecan be expelled from the warhead. By applying the digital techniquesdescribed above to the fragment core design, it is possible toeffectively delay the detonation velocity but in so doing the explosivesector directly between the core and the target must be sacrificed.Although the smallest possible sacrifice is the sector just equal to thesize of the core and located between the lines 226 and 228, a somewhatlarger sector approximately equal to 20 percent of the charge mass andlocated between the lines 230 and 232 is more realistic to allow forcore expansion or dispersion. This sacrificial sector is functionally apart of the core so in effect it adds to the metal mass M whilesubtracting from the charge mass C.

In applying the digital technique to the warhead of FIG. 27, theexplosive ring may be divided into three concentric rings 234, 236 and238 (FIG. 28). The inner annulus 238 is divided into eight reasonablychunky pairs of cells. Eight-way symmetry is desirable for an eight-wayaiming design. The second annulus is divided into twenty chunky cells,or 10 pairs. The outer annulus 234 is divided into 24 cells. Each cellis buffered from its neighbors and will be connected to diodes asnecessary. The numbers of annuli and divisions thereof are somewhatarbitrary. The depth of each annulus will be varied to adjust the timedelay required. Since it is desired that the cells adjacent to thesacrificial section be detonated just as the core leaves the warhead,detonation will be symmetric about the aim line and started on the sideopposite the target. It is de sirable for the outer annulus to lead theinner ones, both to shape the fragment spray and to provide an implodingeffect. In FIG. 28, the various isochrone lines are shown at 240 and thesequence of detonation as indicated by the numbers which represent timeunits achieves the desired result. Detonation is started on both sidesof the aim line in the middle annulus at and both the middle and innerannuli can conveniently have delays at two units/cell. The outerannulus, with more cells to accomplish, is given delays of oneunit/cell. Thus, after about twelve detonation units, the warhead hascompleted its functioning. Now during this time the core should travel asufficient distance to put the core center near the warhead rim, leavingit partly still in contact with the propelling charge.

If the core velocity is, for example, 8,000 feet per second, this meansthat:

12 time units R(feet)/8,000 feet/sec.

foot/8,000/feet/sec. l/l6,000 secs. Thus: I time unit l/l92,000 secs..0052 X exp (3) sec. or 1 time unit 5.2 microseconds. This is wellwithin the delay capability of the digital method, yielding a cellheight of about one-half inch for the outer annulus and about 1 inch forthe inner annuli.

FIG. 29 is a cross section through FIG. 28 showing the relationship ofthe time dilation elements and the extensions which surround the core218.

The warhead designer, plagued by a highly inefficient system from thebeginning (less than 1% of the possible chemical energy of the warheadmass is normally delivered to the target) is loath to tolerate a 20%sacrificial loss in the fragment-core design. A method of partiallyrecouping this loss, potentially applicable to many explosive systemswill now be described with reference to FIG. 30. Although detonation ofthe sacrificial sector in the warhead cannot be permitted, the sectorcan be detonated after ejection or forced to deflagrate. Ejection of thecore is accomplished in about -microseconds so after several hundredmicroseconds the ejected material cannot appreciably influence the corefragmentation whether it detonates or not. Indeed deflagration todetonation transition about 10 milliseconds after ejection would locatethe ejecta near the target with most desirable results.

The ejecta is already segmented into chunks by the digital requirementand these may be expected to at least partially survive ejection forces.Minimal modification to the buffering strength as well as segmenting thecontinuation segments (that is making them more chunky by adding bufferlayers with detonation passthrough areas) would suffice to make theexplosive ejecta a useful part of the kill-mechanism if a practicalmeans of inducing non-detonating decomposition can be found. Pyrocore(or a similar fabrication) is precisely appropriate for theaccomplishment of this task. By threading pyrocore 239 through thesectors 237 (or in the buffer layer 241), decomposition, at the speed ofdetonation, but without detonation itself, may be induced. Such anarrangement of pyrocore in the various sectors is shown in FIG. 30.

FIG. 31 shows a method of increasing the dispersion if over aimingoccurs by use of in-line diodes 240 between the legs of the U-shaped MDFconnectors to make the path length longer in one direction than theother. The assymetry thus induced results in multiple linercollisionsand increased scatter.

A delay technique slightly different and possibly more compact than thatdetailed in FIG. 20 would make use of the interaction between explosiveand metal or other type shock conductors. Explosive slabs 242 arealternated with layers of buffer material 244. Metal caps 246 form shockprisms alternating top and bottom to form a meandering path. Thestraight through paths would allow thinner explosive layers and thestrength of the shock reentering the explosive from the metal prisms canbe focused for local enhancement.

Turning now to an improved method of line initiation of a cylindricalwarhead, an eight-way aiming device will be assumed although theconstructions, as are the ring and detonation control methods, areequally applicable to any number of aiming directions. The conventionalsolution would merely feed the eight outputs from the T-ring of FIGS. 14and 15, via detonating cord, to eight separate line wave generators.Although feasible, this approach is highly inefficient, since eightexplosive layers with sufficient buffering to isolate each would berequired. Such parasitic loss might well ne- The desirability of thiswould depend largely upon the kill-mechanism.

A second alternative, somewhat more complicated, can provide eithermulti-point or continuous line initiation. A typical line wave generator260 (FIG. 34) consists of a triangular piece of explosive sheet withnumerous holes 262 disposed therethrough. The holes are equally spacedin rows parallel to the sides of the device so that when the generatoris detonated at the vertex 264 the shock front must travel a meanderingpath through the gate" between the holes. The shock front is thus brokeninto numerous small fronts which arrive at the base of the triangle withan essentially flat although somewhat-bumpy profile, roughly illustratedby the shock wave line 266.

Instead of a triangular shape, a cylindrical shape which just fits overthe periphery of a cylindrical warhead may be utilized. Holes may be cutin the sheet with the holes arranged in vertical and horizontal rowswith alternated rows staggered. If this cylinder is detonated at onepoint half way between the ends of the cylinder the shock will proceedin both directions around the warhead and collide along a vertical lineon thecylindrical element directly opposite the starting point. Theshock collision can be used in standard ways to propagate into thewarhead either by jutting through a buffer or by using linear AND gatesat the aim points. The line wave cylinder is constructed of explosivesheet at the critical thickness when linear gates are used. Lin-,

ear gates offer the obvious advantages of reliability over thejet-through method.

The reliability of the gate method can be negated in practice since thedetonation collision must occur at the gate junction .with the cylinder.This is best illustrated in FIG. 36 wherein a plurality of gates 270 aredisposed through the buffer ring 272 so that the shock waves travelingabout the explosive ring 274 from the detonation point 276 will meetat278 and pass through the gate 270 into the high explosive charge 280.In the case of certain sheet explosives the size of this target is onlyabout .025 inches.

It would not be possible to merely widen the gates 270 to increase thechance of the short waves meeting at agate since the width of each gatemust be limited Y to prevent the explosion from tuming the corner into.

the first gate the shock wave reaches.

By stacking a series of junctions or gates 282 as shown in FIG. 37, eachseparated by a thin buffer 284, numerous targets can be provided.Collision of the shock fronts at any one of these gates 282 willpropagate the explosion to the appropriate sector radially inwardly.

Unfortunately, the collision has an equal chance of occurring at one ofthe buffer regions 284 and to eliminate failure when this occurs it ispossible to arrange an identical stack of junctions 286 on the oppositeside of the explosive sheet cylinder 288. In this modification shown inFIG. 38, the explosive fingers or pass-through areas 286 are oppositethe buffer regions 284 in the original stack. Thus, no matter where thecollision occurs, one of the fingers is properly positioned to detonate.If the explosion passes through the fingers 286 and explosive path maybe provided at 290 to a linear shaped charge 292 which will shootthrough the buffer material 294 and 296 into the aim sector. The shapedcharge can be made as large as necessary since only one is required ineach of the sectors to be fired.

Still another method of widening the target region for linear gates isshown in FIG. 39 wherein the explosive sheet 300 is divided into twoexplosive paths 302 and 304 with the path 304 nearest the output havingdelays D and D on either side of a set of finger gates 306 similar tothe paths 282 and 286 described above. Assuming the buffers 308 are ofequal width as the diode output and the delays D, D are not quite equal,the shock collision will occur along the outer path 302 away from theoutput well before the shocks collide along the inner path 304. Anotherset of diode fingers 310 are located along the inner path with bufferstrips 312. The inner and outer fingers are aligned so that if theexplosions traveling along the outer path meet adjacent an outer finger306 the explosion will cut across the inner path 304 and through theinner finger aligned with the outer finger. Thus, a set of destructivecross overs are located along the inner path. However, if the collisiontakes place adjacent a buffer strip 308 along the outer path 302, theshocks on the inner path will continue and collide at an explosiveregion with a resultant output.

1 Such an arrangement of cluster fingers (FIG. 39) may be used in FIG.17a to transmit the explosion through the buffer element 164 into theexplosive segments 174. Once an initial segment 174 is detonated thetime sequencing of the detonation of the remaining segments will beaccomplished in accordance with any of the means previously describedabove.

What is claimed is:

1. An explosive device comprising primary explosive charge means dividedinto a plurality of segments, first explosive logic meansinterconnecting said segments in a manner which will determine thedirection and lengthen the path and travel time of the explosion throughall of said segments in sequence subsequent to the detonation of atleast one of said segments and second explosive logic means fordetermining which of said segments will be detonated first, said firstand second explosive logic means thereby controlling the order and timesequencing of the detonation of said segments.

2. An explosive device as set forth in claim 1 further comprisingbufi'er means, substantially isolating said segments from each other.

3. An explosive device as set forth in claim 1, further comprising ahollow cylindrical case, a plurality of said segments being disposedabout said case to form a hollow explosive cylinder and said secondexplosive logic means being comprised of an explosive ring coaxiallydisposed in contiguous relationship with said explosive cylinder.

4. An explosive device as set forth in claim 3 wherein said explosivering is provided with three equally spaced input points adapted to beconnected to a fuse assembly, a pair of opposed explosive diodesintegrally formed in said explosive rings on opposite sides of each ofsaid input points whereby upon detonation of two selected points inproper timed sequence, a selected explosive segment will be detonated.

5. An explosive device as set forth in claim 3 wherein said explosivering is comprised of a U-shaped explosive charge having radiallydirected leg portions substantially thicker than the bight portion andhaving oppositely directed radial explosive fingers connected to themiddle of said bight portion, whereby upon timed detonation of each legat two spaced preselected points the oppositely travelling explosionswill meet to detonate a selected finger.

6. An explosive device as set forth in claim 5 wherein each of saidfingers is disposed contiguous to a segment of said explosive cylinderso that upon initiation of an explosion in one of said fingers, theexplosive segment contiguous thereto will be detonated.

7. An explosive device as set forth in claim 5, wherein a plurality ofsaid rings are concentrically disposed about said explosive cylinder toprovide multi-point ini tiation of said explosive segments.

8. An explosive device as set forth in claim 4, wherein said explosivering is discontinuous and is provided with an initiation point at eachend closely adjacent each other and adapted to be connected to the fuseassembly and further comprising explosive delay means connected to eachof said points and having an effective length longer than thecircumference of said ring to provide an isotopic initiation of theexplosive device if one of said two point should fail to initiate.

9. An explosive device as set forth in claim 3, wherein two closelyadjacent initiation points are located on said ring for connection tothe fuse assembly and further comprising explosive leads connected tosaid ring adjacent each of said points at an angle to prevent detonationthereof upon detonation of the point closest thereto, said explosiveleads providing isotopic detonation of said explosive device on failureof one of said points to initiate.

10. An explosive device as set forth in claim 3 further comprising abuffer ring concentrically arranged with respect to said explosive ringand having a plurality of explosive fingers extending radiallytherethrough, said fingers each being contiguous to a selected explosivesegment whereby upon detonation of said ring at a point substantiallydiametrically opposite a selected finger, the explosions travelling inopposite directions about said ring will meet adjacent said finger todetonate said finger and the explosive segment contiguous thereto.

11. An explosive device as set forth in claim wherein each finger isprovided with a plurality of spaced-apart buffer elements adjacent saidring to pro vide a plurality of connecting points.

12. An explosive device as set forth in claim 11 further comprising anexplosive charge located on the opposite side of said ring from each ofsaid fingers and having a plurality of additional buffer elementsarranged in staggered relationship with respect to said first mentionedbuffer element, shaped charge means in said explosive charge alignedwith said finger to provide an alternate explosive path to said fingerif said explosions meet adjacent one of said first mentioned bufferelements.

13. An explosive device as set forth in claim 11 further comprisingadditional buffer elements disposed on the opposite side of said firstmentioned buffer elements from said explosive ring, explosive delaymeans located in said explosive finger adjacent each end of the firstmentioned buffers to delay the initiation of the explosive intermediatesaid first mentioned buffers and said additional buffers whereby if theexplosions in said ring meet adjacent a buffer element the explosionstravelling through said delays will meet at a point intermediate two ofsaid additional buffer elements to provide detonation of thecontiguousexplosive segment.

14. An explosive device as set forth in claim 2 wherein said firstexplosive logic means comprises a U- shaped length of detonating fuseextending through said buffer means to connect each explosive segmentwith each contiguous explosive segment to provide a time delay betweenthe detonation of successive explosive segments.

15. An explosive device as set forth in claim 14 wherein one leg of saidU-shaped explosive fuse is substantially thinner than the bight portionto define an explosive diode.

16. An explosive device as set forth in claim 15 wherein said explosivesegments are disposed in an array having U-shaped explosive diodesinterconnecting each segment to each contiguous segment said diodesbeing arranged to provide concentric isochrones about the initial pointof detonation in said array.

17. An explosive device as set forth in claim 15 wherein said segmentsare dispersed in a plurality of concentric rings about a central caseand arranged to define oppositely travelling explosive wave fronts of apredetermined character in dependence upon the detonation sequence ofsaid rings along a common radial line.

18. An explosive device as set forth in claim 17 wherein said segmentsare extended to define an explosive cylinder and said case is comprisedof a plurality of individual contiguous fragmentation segments.

19. An explosive device as set forth in claim 18 wherein deflagratableelements are embedded in said explosive segments whereby those segmentsnot detonated prior to the ejection of the case will be detonated uponexposure of said elements.

1. An explosive device comprising primary explosive charge means dividedinto a plurality of segments, first explosive logic meansinterconnecting said segments in a manner which will determine thedirection and lengthen the path and travel time of the explosion throughall of said segments in sequence subsequent to the detonation of atleast one of said segments and second explosive logic means fordetermining which of said segments will be detonated first, said firstand second explosive logic means thereby controlling the order and timesequencing of the detonation of said segments.
 2. An explosive device asset forth in claim 1 further comprising buffer means, substantiallyisolating said segments from each other.
 3. An explosive device as setforth in claim 1, further comprising a hollow cylindrical case, aplurality of said segments being disposed about said case to form ahollow explosive cylinder and said second explosive logic means beingcomprised of an explosive ring coaxially disposed in contiguousrelationship with said explosive cylinder.
 4. An explosive device as setforth in claim 3 wherein said explosive ring is provided with threeequally spaced input points adapted to be connected to a fuse assembly,a pair of opposed explosive diodes integrally formed in said explosiverings on opposite sides of each of said input points whereby upondetonation of two selected points in proper timed sequence, a selectedexplosive segment will be detonated.
 5. An explosive device as set forthin claim 3 wherein said explosive ring is comprised of a U-shapedexplosive charge having radially directed leg portions substantiallythicker than the bight portion and having oppositely directed radialexplosive fingers connected to the middle of said bight portion, wherebyupon timed detonation of each leg at two spaced preselected points theoppositely travelling explosions will meet to detonate a selectedfinger.
 6. An explosive device as set forth in claim 5 wherein each ofsaid fingers is disposed contiguous to a segment of said explosivecylinder so that upon initiation of an explosion in one of said fingers,the explosive segment contiguous thereto will be detonated.
 7. Anexplosive device as set forth in claim 5, wherein a plurality of saidrings are concentrically disposed about said explosive cylinder toprovide multi-point initiation of said explosive segments.
 8. Anexplosive device as set forth in claim 4, wherein said explosive ring isdiscontinuous and is provided with an initiation point at each endclosely adjacent each other and adapted to be connected to the fuseassembly and further comprising explosive delay means connected to eachof said points and having an effective length longer than thecircumference of said ring to provide an isotopic initiation of theexplosive device if one of said two point should fail to initiate.
 9. Anexplosive device as set forth in claim 3, wherein two closely adjacentinitiation points are located on said ring for connection to the fuseassembly and further comprising explosive leads connected to said ringadjacent each of said points at an angle to prevent detonation thereofupon detonation of the point closest thereto, said explosive leadsproviding isotopic detonation of said explosive device on failure of oneof said points to initiate.
 10. An explosive device as set forth inclaim 3 further comprising a buffer ring concentrically arranged withrespect to said explosive ring and having a plurality of explosivefingers extending radially therethrough, said fingers each beingcontiguous to a selected explosive segment whereby upon detonation ofsaid ring at a point substantially diametriCally opposite a selectedfinger, the explosions travelling in opposite directions about said ringwill meet adjacent said finger to detonate said finger and the explosivesegment contiguous thereto.
 11. An explosive device as set forth inclaim 10 wherein each finger is provided with a plurality ofspaced-apart buffer elements adjacent said ring to provide a pluralityof connecting points.
 12. An explosive device as set forth in claim 11further comprising an explosive charge located on the opposite side ofsaid ring from each of said fingers and having a plurality of additionalbuffer elements arranged in staggered relationship with respect to saidfirst mentioned buffer element, shaped charge means in said explosivecharge aligned with said finger to provide an alternate explosive pathto said finger if said explosions meet adjacent one of said firstmentioned buffer elements.
 13. An explosive device as set forth in claim11 further comprising additional buffer elements disposed on theopposite side of said first mentioned buffer elements from saidexplosive ring, explosive delay means located in said explosive fingeradjacent each end of the first mentioned buffers to delay the initiationof the explosive intermediate said first mentioned buffers and saidadditional buffers whereby if the explosions in said ring meet adjacenta buffer element the explosions travelling through said delays will meetat a point intermediate two of said additional buffer elements toprovide detonation of the contiguous explosive segment.
 14. An explosivedevice as set forth in claim 2 wherein said first explosive logic meanscomprises a U-shaped length of detonating fuse extending through saidbuffer means to connect each explosive segment with each contiguousexplosive segment to provide a time delay between the detonation ofsuccessive explosive segments.
 15. An explosive device as set forth inclaim 14 wherein one leg of said U-shaped explosive fuse issubstantially thinner than the bight portion to define an explosivediode.
 16. An explosive device as set forth in claim 15 wherein saidexplosive segments are disposed in an array having U-shaped explosivediodes interconnecting each segment to each contiguous segment saiddiodes being arranged to provide concentric isochrones about the initialpoint of detonation in said array.
 17. An explosive device as set forthin claim 15 wherein said segments are dispersed in a plurality ofconcentric rings about a central case and arranged to define oppositelytravelling explosive wave fronts of a predetermined character independence upon the detonation sequence of said rings along a commonradial line.
 18. An explosive device as set forth in claim 17 whereinsaid segments are extended to define an explosive cylinder and said caseis comprised of a plurality of individual contiguous fragmentationsegments.
 19. An explosive device as set forth in claim 18 whereindeflagratable elements are embedded in said explosive segments wherebythose segments not detonated prior to the ejection of the case will bedetonated upon exposure of said elements.